One of the most important problems to be solved in managing any production line is the achievement of the greatest possible result with a given operative configuration of the machines forming the line itself. That means the possibility of controlling the product flow during the whole process and the possibility of supplying the downstream machine with said products depending upon the working step and the production capacity of the machine itself.
Such a problem is for example to be solved between the machine or machines for the manufacture of any product and the machine or machines designed to wrap or pack it.
On coming out of the manufacturing machines, finished products are usually disposed according to one or more continuous rows whereas the wrapping machines need to receive the products individually spaced apart or in groups and fed at the same speed with which they come out of the manufacturing machine or machines.
For this purpose a device designed to space apart the products and to form different groups is usually provided between the manufacturing machines and the wrapping machines.
Most devices of this kind comprise a continuously moved conveyor, a pair of members adapted to intercept the first product of the continuous row, and gripping elements acting on the first product of the second group. Upon request of another group, downstream of this device, the intercepting members are deactivated; the group being free to move along the conveyor. Then the gripping elements too are deactivated and, after a certain lapse of time, necessary for the passage of a group of products, the intercepting members stop the first product of the second, now first, group. As a result, all of the continuous row is activated. Finally, the gripping elements too are activated again and they act now on the first product of the third, now second, group of the continuous row.
Other devices adopt solutions in which at regular intervals they act on the moving-forward products and impart a certain acceleration to the same so that they are spaced apart from the rest of the row.
In many cases said acceleration is imparted to the products by powered belt conveyors which at regular intervals are pressed against the products as they move forward.
However, as it is not possible to check the acceleration degree, in order to be sure that said products may at least receive a sufficient acceleration, it is necessary to impart to them the maximum acceleration possible, which causes the products to be ill-treated.
However sometimes a machine located upstream or downstream of this device may happen to be temporarily stopped for any reason, for example due to a clogging caused by the product or the paperboard or because it is necessary to change the wrapping band.
Should for example a manufacturing machine temporarily stop, the products could come to the acceleration device disposed in irregular groups and not on a continuous row, which would cause the wrapping machine to stop, that is, to wait for the regular feed of the products to be restored and this would be unproductive.